Method and device for configuring link in wireless lan system

ABSTRACT

A method and device for configuring a link in a wireless LAN system are disclosed. The wireless link configuration method comprises the steps of: acquiring a first probe request message transmitted by a first mobile terminal; delaying the transmission of a second probe request message when the first probe request message is similar to the second probe request message which is prepared for transmission by a second mobile terminal; receiving a probe response message, which is a response to the first probe request message, from a wireless access device; and withdrawing the transmission of the second probe request message when information included in the probe response message satisfies requirements of the second mobile terminal. Therefore, a time for configuring a link between wireless LAN devices can be reduced.

TECHNICAL FIELD

A variety of example embodiments according to the present inventiongenerally relate to configuration of a wireless link, and morespecifically to methods and devices for rapidly configuring an initiallink in a wireless local area networking (WLAN) system.

BACKGROUND ART

Currently, according to wide distribution of mobile stations, a wirelesslocal area networking (WLAN) technology which can provide fasterwireless internet services to the mobile stations is becomingremarkable. The WLAN technology is a technology which can make mobilestations such as smart phones, smart pads, laptop computers, portablemultimedia players, embedded devices, etc. able to wirelessly access aninternet in home, company, or specific service provision areas, based onwireless communication technologies.

DISCLOSURE Technical Problem

The present invention is to provide methods for configuring a wirelesslink between WLAN devices in a congested environment having a largenumber of wireless devices.

Also, the present invention is to provide apparatuses for configuring awireless link between WLAN devices in a congested environment having alarge number of wireless devices.

Technical Solution

In order to achieve the purposes of the present invention, according toan example embodiment according to the present invention, a method maybe provided for configuring a wireless link and performed in a secondmobile station. The method may comprise obtaining a first probe requestmessage transmitted from a first mobile station; delaying transmissionof the second probe request message when the first probe request messageis similar to a second probe request message which the second mobilestation prepares to transmit; receiving a probe response message from awireless access station in response to the first probe request message;and cancelling the transmission of the second probe request message wheninformation included in the probe response message satisfiesrequirements of the second mobile station.

Here, in the delay transmission of the second probe request message,when service set identifiers (SSID) of the first probe request messageand the second probe request message coincide with each other, thesecond probe request message may be delayed for at least a maximumchannel time (MaxChannelTime).

Here, the method may further comprise transmitting the second proberequest message, when capability information included in the proberesponse message does not satisfy the requirements of the second mobilestation.

Here, the method may further comprise requesting authentication to thewireless access station by using wireless access information obtainedfrom the probe response message.

In order to achieve the purposes of the present invention, according toanother example embodiment according to the present invention, thesecond mobile station may comprise a control part controlling operationsof the second mobile station, and at least one network interface cardfor transmitting and receiving data based on commands of the controlpart. Also, the control part may obtain a first probe request messagetransmitted from a first mobile station, delay transmission of thesecond probe request message when the first probe request message issimilar to a second probe request message which the second mobilestation prepares to transmit, receive a probe response message from awireless access station in response to the first probe request message,and cancel the transmission of the second probe request message wheninformation included in the probe response message satisfiesrequirements of the second mobile station.

Here, when service set identifiers (SSID) of the first probe requestmessage and the second probe request message coincide with each other,the control part may delay the second probe request message for at leasta maximum channel time (MaxChannelTime).

Here, the control part may transmit the second probe request message,when capability information included in the probe response message doesnot satisfy the requirements of the second mobile station.

Here, the control part may request authentication to the wireless accessstation by using wireless access information obtained from the proberesponse message.

Advantageous Effects

According to example embodiments of the present invention, a time neededfor configuring wireless links between WLAN devices can be reduced whena large number of WLAN devices request wireless link configurations in acongested area. Especially, according to example embodiments of thepresent invention, when multiple mobile stations transmit a plurality ofprobe request messages at the same time, the time needed for configuringwireless links can be reduced by minimizing collisions between proberesponse messages corresponding to the probe request messages.

DESCRIPTION OF DRAWINGS

FIG. 1 conceptually illustrates an example configuration of a WLANsystem to which embodiments of the present invention can be applied.

FIG. 2 conceptually illustrate a step in which MS configures a link withAP according to an example embodiment of the present invention.

FIG. 3 illustrates a passive scanning step of MS related to an exampleembodiment of the present invention.

FIG. 4 illustrates an active scanning step of MS related to an exampleembodiment of the present invention.

FIG. 5 is a block diagram which conceptually illustrates a mobilestation (MS) 100 related to an example embodiment of the presentinvention.

FIG. 6 is a block diagram which conceptually illustrates an access point200 related to an example embodiment of the present invention.

FIG. 7 is a flow chart illustrating a WLAN access procedure according toan example embodiment of the present invention for a case in which aplurality of mobile stations try to access an AP simultaneously.

FIG. 8 illustrates a detailed logic of a first analysis in the exampleembodiment of FIG. 7.

FIG. 9 illustrates a detailed logic of a second analysis in the exampleembodiment of FIG. 7.

FIG. 10 illustrates a packet structure of a beacon message transmittedby AP according to the present invention.

FIG. 11 illustrates a packet structure of a probe request messagetransmitted by MS according to the present invention.

FIG. 12 illustrates a packet structure of a probe response messagetransmitted by AP according to the present invention.

MODE FOR INVENTION

Since embodiments described in the present specification are intended toclearly describe the spirit of the present invention to those skilled inthe art to which the present invention pertains, the present inventionis not limited to those embodiments described in the presentspecification, and it should be understood that the scope of the presentinvention includes changes or modifications without departing from thespirit of the invention.

The terms and attached drawings used in the present specification areintended to easily describe the present invention and shapes shown inthe drawings are exaggerated to help the understanding of the presentinvention if necessary, and thus the present invention is not limited bythe terms used in the present specification and the attached drawings.

In the present specification, detailed descriptions of knownconfigurations or functions related to the present invention which havebeen deemed to make the gist of the present invention unnecessarilyobscure will be omitted below.

Hereinafter, a method and a device for fast accesses between WLANdevices using a plurality of communication channels according toembodiments of the present invention will be described.

Among standards of WLAN technologies, standardization on Medium AccessControl (MAC) and Physical (PHY) layers are going on in an Institute ofElectrical and Electronics Engineers (IEEE) 802.11 working group.

FIG. 1 conceptually illustrates an example configuration of a WLANsystem to which embodiments of the present invention can be applied.

Referring to FIG. 1, the WLAN system may include one or more basicservice sets (BSS) 211 and 221. The BSS 211 or 221 is a set of stationswhich can communicate with each other, and managed by an access point(AP) 210 or 220. A mobile station (MS) 110 or 120 may perform a role ofproviding wireless internet services to a user by accessing the AP 210or 220 according to IEEE 802.11 WLAN standards. The BSS 211 or 221 maybe classified into an infrastructure BSS and an independent BSS, and theinfrastructure BSS is illustrated in FIG. 1. The BSS-1 211 is managedand operated by the AP-1 210, and one or more MSs including MS-1 110 andMS-2 120 may receive WLAN services through the AP-1 210. Also, the AP-1210 is connected to the AP-2 220 through a distribution system (DS) 300.The BSSs 211 and 221 connected through the DS 300 may form an extendedservice set (ESS) 410. Since the detail of configurations of WLANsystems is described in the standard specifications such as IEEE802.11-2012 (Mar. 29, 202), explanation on the detail will be omittedherein. The contents of the standard specifications may be combined tothe present description for reference.

FIG. 2 conceptually illustrate a step in which MS configures a link withAP according to an example embodiment of the present invention.

Referring to FIG. 2, a procedure for MS 100 to access AP 200 maycomprise three steps—scanning, authentication, and association. Thescanning step is a step in which the MS 100 obtains access informationof a BSS operated by the AP 200. For the scanning, there are a passivescanning technique S101 that obtains information by using beaconmessages which are periodically transmitted by the AP, and an activescanning technique in which the MS transmits a probe request to the AP(S103), receives a probe response from the AP (S105), and obtains accessinformation from the probe response.

The MS 100 which successfully receives the wireless access informationin the scanning step may perform the authentication step by transmittingan authentication request (S107 a) and receiving an authenticationresponse (S107 b). After successful completion of the authenticationstep in the IEEE 802.11 layer, the association step (S109 a and S109 b)may be performed. In addition, authentication based on 802.1X (S111) anda step of obtaining IP address through DHCP (S113) may be performed.

FIG. 3 illustrates a passive scanning step of MS related to an exampleembodiment of the present invention. Referring to FIG. 3, the MS-1 110according to the present invention may obtain wireless accessinformation or respective APs by receiving beacon message which areperiodically transmitted by AP-1 210 and AP-2 220 located adjacently.

FIG. 4 illustrates an active scanning step of MS related to an exampleembodiment of the present invention.

Referring to FIG. 4, the MS-1 110 according to the present invention maytransmits a probe request message to obtain information of APs locatedadjacently, and obtain wireless access information of respective APs byreceiving the corresponding probe response messages from AP-1 210 andAP-2 220.

FIG. 5 is a block diagram which conceptually illustrates a mobilestation (MS) 100 related to an example embodiment of the presentinvention.

Referring to FIG. 5, the MS 100 according to the present invention maycomprise at least one network interface cards (NIC) 111 to 119performing a WLAN access through an AP. The network interface cards 111to 119, modules for performing WLAN access, may be embedded within theMS or installed in outside of the MS. The network interface cards 111 to119 may perform wireless communications with the AP according torespective supported WLAN specifications. Also, among the networkinterface cards 111 to 119, only one NIC may operate at a time or aplurality of NICs may simultaneously operate according to performance ofthe MS 100 or system requirements. In the MS 100 of FIG. 5, the multipleNICs 111 to 119 are illustrated as separated, and MAC and PHY layers ofeach NIC may operate independently from each other. These NICs 111 to119 may be implemented as a functional entity which can be separatedphysically or as a single integrated physical entity.

A mobile communication module 120 may make the MS 100 transmit andreceive wireless signals to/from an external device in a mobilecommunication network.

A user interface part 130 may make commands for controlling the MS 100be input by a user. A display part 140 may display results fromoperations of the MS 100, status of the MS 100, and information providedby the AP.

A memory part 150 may store access program codes for controlling accessto the AP, and various data for the program codes.

A control part 160 may perform a role of controlling each of the NICs111 to 119 to make the MS 100 try to access the AP through anappropriate frequency band by using access information provided by theAP and user/system requirements.

FIG. 6 is a block diagram which conceptually illustrates an access point200 related to an example embodiment of the present invention.

Referring to FIG. 6, the AP 200 according to the present invention maycomprise at least one network interface cards (NIC) 211 to 219 foroperating BSS in one or more frequency bands. The network interfacecards 211 to 219, modules for performing WLAN access, may be embeddedwithin the AP 200 or installed in outside of the AP 200. The NICs 211 to219 may perform wireless communications with the MS according torespective supported WLAN specifications. Also, among the networkinterface cards 211 to 219, only one NIC may operate at a time or aplurality of NICs may simultaneously operate according to performance ofthe AP 200 or system requirements. In the AP 200 of FIG. 6, a pluralityof NICs 211 to 219 are illustrated as separated, and MAC and PHY layersof each NIC may operate independently from each other. These NICs 211 to219 may be implemented as a functional entity which can be separatedphysically or as a single integrated physical entity.

A memory part 250 may store access program codes for controlling accessfrom mobile stations, and various data for the program codes. A controlpart 260 may perform a role of controlling each of the NICs 211 to 219to make the AP 200 process access from MS through an appropriatefrequency band by using access information for multiple frequency bandsand user/system requirements.

FIG. 7 is a flow chart illustrating a WLAN access procedure according toan example embodiment of the present invention for a case in which aplurality of MSs try to access an AP simultaneously, FIG. 8 illustratesa detailed logic of a first analysis in the example embodiment of FIG.7, and FIG. 9 illustrates a detailed logic of a second analysis in theexample embodiment of FIG. 7.

Referring to FIGS. 7 to 9, a first mobile station 100 may transmit afirst probe request message (S103, S103 a). Also, a second mobilestation 400 may obtain (i.e., overhear) the first probe request messagetransmitted from the first mobile station 100.

The second mobile station 400 may determine similarity between a secondprobe request message which the second mobile station prepares totransmit and the first probe request message. As a result, when thesecond probe request message is similar to the first probe requestmessage, the second mobile station 400 may delay transmission of thesecond probe request message (S202). In this case, the second mobilestation 400 may delay the transmission of the second probe requestmessage for at least a maximum channel time (e.g., ‘MaxChannelTime’).

For example, when a SSID included in the first probe request messagecoincides with a SSID included in the second probe request message, thesecond mobile station 400 may determine that the first probe requestmessage is similar to the second probe request message.

On the contrary, when the SSID included in the first probe requestmessage is different from the SSID included in the second probe requestmessage, the second mobile station 400 may determine that the firstprobe request message is different from the second probe requestmessage. In this case, the second mobile station 400 may transmit thesecond probe request message without delaying.

Also, the second mobile station 400 may further analyze similaritybetween the probe request messages by using other items in addition tothe SSID. For example, in case that access information (e.g., frequencyband information, transmission speed, load information, and so on) isincluded in the probe request message, the second mobile station 400 mayanalyze similarity between first access information included in thefirst probe request message and second access information included inthe second probe request message, and may determine that the first proberequest message is similar to the second probe request message when theaccess information of both messages coincides with each other. Here, asan example of the further analysis, access information is suggested.However, methods of configuring wireless links according to the presentinvention are not limited to the above-described example.

Meanwhile, the wireless access station 200 may transmit a probe responsemessage (or, a beacon message) in response to the first probe requestmessage (S105, S105 a). The first mobile station 100 may receive theprobe response message (or, the beacon message) from the wireless accessstation 200.

The second mobile station 400 may obtain (i.e., overhear) the proberesponse message (or, the beacon message) from the wireless accessstation 200. Then, the second mobile station 400 may determine whethercapability information included in the probe response message satisfiesits requirements, and may discard transmission of the second proberequest message when the capability information satisfies itsrequirements (S206).

On the other hand, the second mobile station 400 may transmit the secondprobe request message when the capability information included in theprobe request message does not satisfy its requirements.

Also, the second mobile station 400 may determine whether to discardtransmission of the second probe request message by using otherinformation in addition to the capability information. For example, ifthe probe response message includes access information (i.e., frequencyband information, transmission speed, load information, etc.), thesecond mobile station 400 may determine whether the access informationincluded in the probe response message satisfies its requirements, anddiscard transmission of the second probe request message when the accessinformation satisfies its requirements.

On the other hand, the second mobile station 400 may transmit the secondprobe request message when the capability information included in theprobe response message does not satisfy its requirements. Here, althoughthe access information is suggested as an example of the furtheranalysis. However, methods of configuring wireless links according tothe present invention are not limited to the above-described example.

Meanwhile, when the first mobile station 100 receives the probe responsemessage, the first mobile station 100 may transmit a firstauthentication request message to the wireless access station 200(S107). After then, the first mobile station 100 may perform anauthentication step and an association step so as to access the wirelessaccess station 200.

When the second mobile station 400 receives the probe response message,the second mobile station may transmit a second authentication requestmessage to the wireless access station 200 (S207). Then, the secondmobile station 400 may perform an authentication step and an associationstep so as to access the wireless access station 200.

FIG. 10 illustrates a packet structure of a beacon message transmittedby AP according to the present invention.

Referring to FIG. 10, a wireless access station (i.e., the wirelessaccess station 200 of FIG. 7) may transmit a beacon message including aframe control field, a duration/ID field, a destination address field, asource address field, a basic service set (BSS) ID field, a sequencecontrol field, a frame body field, and a frame check sequence (FCS)field.

Here, the frame body field may include a timestamp field, a beaconinterval field, a capability field, a service set identifier (SSID)field, a supported rates field, an operating band (OB) field, anoperating channel (OC) field, etc.

Meanwhile, information of fields in the frame body field excluding theOB field and the OC field may mean BSS information (i.e., BSSI). Thatis, BSSI may include the timestamp field, the beacon interval field, thecapability field, the service set identifier (SSID) field, and thesupported rates field.

FIG. 11 illustrates a packet structure of a probe request messagetransmitted by MS according to the present invention.

Referring to FIG. 11, a mobile station (i.e., the mobile station 100 orthe mobile station 400 in FIG. 7) may transmit a probe request messageincluding a frame control field, a duration/ID field, a destinationaddress field, a source address field, a basic service set (BSS) IDfield, a sequence control field, a frame body field, and a frame checksequence (FCS) field.

Here, the frame body field may include a service set identifier (SSID)field, a supported rates field, a supporting band (SB) field, etc.

FIG. 12 illustrates a packet structure of a probe response messagetransmitted by AP according to the present invention.

Referring to FIG. 12, a wireless access station (i.e., the wirelessaccess station 200 of FIG. 7) may transmit a probe response messageincluding a frame control field, a duration/ID field, a destinationaddress field, a source address field, a basic service set (BSS) IDfield, a sequence control field, a frame body field, and a frame checksequence (FCS) field.

Here, the frame body field may include BSSI for NIC-1, BSSI for NIC-2, .. . and BSSI for NIC-m.

1. A method of configuring a wireless link, performed in a second mobilestation, the method comprising: obtaining a first probe request messagetransmitted from a first mobile station; when the first probe requestmessage is similar to a second probe request message which the secondmobile station prepares to transmit, delaying transmission of the secondprobe request message; receiving a probe response message from awireless access station in response to the first probe request message;and when information included in the probe response message satisfiesrequirements of the second mobile station, cancelling the transmissionof the second probe request message.
 2. The method of claim 1, wherein,in the delay transmission of the second probe request message, whenservice set identifiers (SSID) of the first probe request message andthe second probe request message coincide with each other, the secondprobe request message is delayed for at least a maximum channel time(MaxChannelTime).
 3. The method of claim 1, further comprisingtransmitting the second probe request message, when capabilityinformation included in the probe response message does not satisfy therequirements of the second mobile station.
 4. The method of claim 1,further comprising requesting authentication to the wireless accessstation by using wireless access information obtained from the proberesponse message.
 5. A second mobile station comprising: a control partcontrolling operations of the second mobile station; and at least onenetwork interface card for transmitting and receiving data based oncommands of the control part, wherein the control part obtains a firstprobe request message transmitted from a first mobile station, delaystransmission of the second probe request message when the first proberequest message is similar to a second probe request message which thesecond mobile station prepares to transmit, receives a probe responsemessage from a wireless access station in response to the first proberequest message, and cancels the transmission of the second proberequest message when information included in the probe response messagesatisfies requirements of the second mobile station.
 6. The station ofclaim 5, wherein, when service set identifiers (SSID) of the first proberequest message and the second probe request message coincide with eachother, the control part delays the second probe request message for atleast a maximum channel time (MaxChannelTime).
 7. The station of claim5, wherein the control part transmits the second probe request message,when a capability element included in the probe response message doesnot satisfy the requirements of the second mobile station.
 8. Thestation of claim 5, wherein the control part requests authentication tothe wireless access station by using wireless access informationobtained from the probe response message.